Gathering Information.

The first thing to do when Confluence freezes or becomes unresponsive (but the Java process is still running) is to take four thread dumps, separated by 30 seconds between each dump. Thread dumps will show what threads are currently running, (what Confluence is currently doing at the moment the thread dump is taken) and will greatly help diagnosing your issue.

Java Seg Faults

Out of Memory: Permgen space

Search the atlassian-confluence.log file for the text java.lang.OutOfMemoryError: PermGen space. You can solve this problem by increasing your PermGen space to 256M. Make sure to specify PermGen space as opposed to heap space. PermGen space is a straight-forward increase of the memory setting.

Out of Memory: Heap space

Unlike PermGen space, Heap space memory may indicate a memory leak and can require more troubleshooting than just increasing the amount. Managing memory settings requires some analysis; there is no appropriate universal recommendation. To determine if your heap space memory is too low, make sure your XML backup is disabled (see below) and enter plugin safe mode to eliminate memory leak possibilities from our two most likely sources. Once you've done that, read through our suggestions for setting the ideal settings for your environment.

In some cases, these plugins may need upgrading or other maintenance. In some cases they must be disabled. On each plugin's page, you can browse the jira issues. Try entering plugin safe mode for troubleshooting purposes.

Remote API

Remote API scripts can hammer Confluence into submission! If you've recently added a script, remove it for troubleshooting purposes or disable the Remote API.